Abstract Over 11 million Americans aged 12 or older reported opioid misuse in 2016. Over 40,000 people died due to opioid-related overdoses in 2016, up 345% from 2001 to 2016. Preventing the onset of opioid misuse is critical for young adults, who represent 2.5 million past year opioid misusers. Opioid misuse in this developmental period can negatively affect mental, physical, and social well-being and can lead to morbidity and mortality due to overdose. Young adults entering the workforce are especially susceptible to substance use. In the workplace, annual overdose deaths from the non-medical use of drugs or alcohol have risen by 38% from 2013 to 2016 and 70% of employers have reported negative consequences of opioid misuse. Despite these rates of use and negative consequences, only 24% of employers offer workplace prevention of these dangers. Construction trade workers have the highest proportional mortality ratio for premature death by opioid overdose. Broad normalization of pain, injury, musculoskeletal disorders, and psychological distress associated with chronic pain, safety conditions, job insecurity, and unsatisfactory work arrangements may contribute to opioid misuse among this workforce. At the present time, primary prevention efforts have not addressed the significant impact of opioid misuse on young adult construction trade workers. The objective of this study is to is to develop an optimized, highly effective and efficient mobile-friendly web-based intervention that is immediately scalable and focused on preventing opioid misuse among young adult construction trade workers. This Phase I study will use the Preparation phase of the Multiphase Optimization Strategy (MOST) approach which includes the development of a comprehensive, evidence-based framework that identifies causal pathways to intervene on which is essential to developing effective and sustainable behavioral interventions. This formative work will guide the development and assessment of a behavioral intervention that is feasible, culturally competent, and targets empirically established mediators. The specific aims of this study are to 1) Develop a storyboard for a behavioral intervention based on our theory- and expert- informed conceptual model; 2) Produce a fully functional intervention component prototype; and 3) Pilot test the intervention component prototype to assess preliminary scientific and technical merit as well as the validity of the conceptual model. Fulfillment of these aims will ultimately position the research team to propose a Phase II SBIR grant focused on an optimization trial(s) (i.e. identification of the most effective intervention components to be included in the full intervention) and rigorous evaluation of a feasible, technically sound, and commercially viable opioid misuse prevention program.